Paint, varnish, and lacquer remover



Patented Nov. 28, 1950 2,531,828 PAINT, VARNISH, AND LACQUER REMOVEBEdwin P. Peterson, Brooklyn, and Oscar P. Muller,

New York, N.

Y., assignors to National Lead Company, New York N. Y., a corporation ofv New Jersey No Drawing. Application March 29, 1947, 1 Serial No.738,235

11 Claims. 01. 252-103) This invention relates generally to bodiedsolvents and more particularly. to solvents of the character adapted forsoftening and removal of coatings of the character of paint, varnish,lacquers and the like.

One of the objects of this invention is to provide a novel solvent.

Another object is to provide a process of making such a solvent.

. Further objects will appear from the detailed description in whichwill be set out illustrative embodiments of this invention; it is to beunderstood, however, that this invention is susceptible of variousembodiments within the scope of the appended claims.

Generally stated and in accordance with illustrative embodiments of thisinvention, the bodied solvent has colloidally dispersed therein amodifled clay, originally exhibiting a substantial baseexchange capacityand in which the inorganic cation has been replaced by a substitutedonium base of the character hereinafter described, in order to exhibit asubstantial'gelling characteristic in the solvent.

In accordance with a process embodying this invention, the modified clayis colloidally dispersed in the solvent soas tobody the same.

The solvent may be any suitable organic liquid 'or combinations ormixtures of solvents which may be employed for various purposes, viz.,to soften and facilitate the removal of paints, varnishes, lacquers andother coatings which it may be desired toremove.

When solvent mixtures are applied .on the coatings such as paint,varnish. lacquers and the like, they spread ,to a thin film due to theirlow viscosity and are not suitable for removing Such coatings fromvertical surfaces. Furthermore, because of spreading rapidly into thinfilms, these solvents evaporate too rapidly to soften the coating and.would have to be applied many times in order to be efiective. In orderto avoid these less easy replacement.

difficulties and to be able to apply the remover in a heavy him and toprevent the solvents from spreading excessively and running on verticaland inclined surfaces, it is customary to thicken the composition bymeans of various additives.

Many agents have been suggested and used for thickening paint removersand are mentioned in the literature, principally cellulose esters, waxcompounds or combinations of both or metal soaps in the form ofstearates. Such gelling agents are not volatile and constitute a residueafterevaporation of the solvents which adversehw aflects the propertiesof coatings applied over 5 clay-acid with bases such as t line-earthmetal hydroxides.

them and must be removed more or less completely before new paint can beapplied. Furthermore, in most cases it is difiicult to form thixotropicgels heavy enough to prevent running or sagging on vertical surfaces.The incorporation of these agents into the solvent mixture requiresspecial processing and in some cases the preparation of the gellingagents themselves are lengthy and timeconsumlng.

The clays which are useful as starting materials for making the modifiedclay in accordance with this invention are those exhibiting substantialbase-exchange properties, and particularly those exhibitingcomparatively high base-exchange properties, and particularl thoseexhibiting comparatively high base-exchange properties and containingcations capable of more or The clays particularly contemplated by thespecification and the claims,

. include themontmcrillonites, viz., sodium, po-

tassium; lithium and other bentonites, particular- 1y those of theWyoming type; magnesium bentonite (sometimes called heetorite) andsaponite; also nontronl'te and attapulgite, particularly that of theGeorgia-Florida type. These clays, characterized by an unbalancedcrystal lattice, are believed to have negative charges which'arenormally neutralized by inorganic cations.v As found in nature,therefore, they exist as salts of the weak the alkalior alka- Thebase-exchange capacities of the various clays enumerated run from about25 to about 100, based upon milliequivalents of exchangeable base per100 grams of clay. The montmorillonites have comparatively highbase-exchange capacities, viz., -100. Attapulgite has substantialbase-exchange capacity, vizL, 2545. Generally, the clays of higherbase-exchange capacities are particularly useful where high exchange ofan organic base for the cation of the clay is desired.

More specifically, and in accordance with illustrative embodiments ofthis invention, a clay of the character described and exhibitingsubstantial base-exchange capacity, is reacted with an. organiccompound, more particularly one hereinafter generally defined andreferred to as an "onium" compound, by the substitution, for the claycation, of the cation of the organic compound, which cation is of aclass hereinafter referred to as an oniunf base. This invention is not,however, restricted to the use of a reaction product of a base-salt withclay-salt, but includes thereaction product'of a free base with anacidciay. I

, nary ammonium I compoimds such 'tetra- Preparation of a modified claygelling agent 600 g. of a Wyoming bentonite was added to 1B liters ofwater and the slurry allowed to stand for two hours to settle out thenon-clay impurities. 9.9 g. (0.1 mol) of 36% concentrated hydrochloricacid was added to 26.05 g. (0.1 mol) of octadecylamlne, and theoctadecylammonium chloride formed was then dissolved in three liters ofhot water. The hot solution was added to 2924 ml. of the grit-freebentonite slurry. F106- hibits good gelling properties in water.Howeveiu,

some non-swelling clays whenconverted to the onium salt form will swellin organic liquids-and give rise to thixotropic colloidal dispersions.

It is to be understood that when reference is made to basic organiccompounds such as amines,

it is implied that before reacting with the clay by' base-exchange,the'amine is converted to the onium form either by the addition of acidor by reason of the fact that-some part of the inorganic base in thenaturally occurring clay consists at hydrogen.

In the preparation of organic gels various methods may be followed. Ifit is desired to prepare a gelfreefrom abrasive impurities it ,may beadvantageous to start with a dilute aqueous dispersion of bentonite andallow the non-bentonite impurities to settle out, or to remove them bysupercentrifuging. By the latter method it is also possible tofractionate tlie clay into any desired particle size fraction.Thereafter, the purified bentonite dispersion is reacted with a salt ofthe desired amine or other basic organic compound. The flocculated oniumbentonite is then filtered, dried, ground and mixed with the organicliquid which is to be bodied up. For-rapidly accomplishing dispersion ofthe onium bentonite in the organic liquid. it is often advantageoustoheat the mixture and pass it through a multiple-roll mill such as apaint mill, although this is not necessary for some combinations. I

Where impurities associated with the clay are of no consequence, it isoften sufllcient merely to add the dry clay to the organic liquidcontaining suilicient amine salt or salts of other basic organiccompound to more or less completely react with the clay. The gellingeffect is thus enhanced by converting the amine-to the salt form, or anyof the other basic organic compounds to the onium form, either before orafter the addition of the clay, by introduction of an acid such ashydrochloric or acetic acid. Further, it isalso feasible to prepare adry mixture, to be used in culation of the bentonite occurredimmediately upon addition of the hot amine salt solution, and theprecipitate was filtered, washed, dried and pulverized. The product wasreserved for fur the re use. 7

gel formation, by mixing the amine with dry clay and then mixing in therequisite amount of an acid such as acetic or by mixing the amine saltwith the dry clay, thereafter adding the dry amine-bentonite mixture vto the liquid with, which it is desired to produce a gel.

Such gels vary in consistency (stiffness) depending on the amount ofonium bentonite used specific examples given.

Preparation of a modified clay gelling agent 0 119.4 g. of dry steam Jetmilled bentonite, containing 6.3% moisture and 10% non-clay impuritieswas weighed into a mortar. 18.52 g. (0.1 mol) of dodecylamine and 6.05g. (0.1 moi) of glacial acetic acid were added and intimately mixed witha pestle until a homogeneous smooth powder resulted. The product wasreserved for further use.

EXAMPLE 3 Preparation of paint remover The following ingredients weremixed together:

- Parts by weight Methyl-isobutyl-ketone 24.0 Denatured ethyl alcohol24.5 Toluol 41.5

Octadecyl-ammonium bentonite of Ex. l 10.0

ingredients added. The product was successfully used as alacquer'remover.

EXAMPLE .4

The composition described in Example 3 was used, with the exceptionthat=the octadecylammonium bentonite of Example-1 was replaced by thedodecylammonium bentonite of Example 2. In preparing the composition,the solvents were first intermixed and then the dodecylam moniumbentonite of Example 2 was added at room temperature and the mixturestirred. The resultant product was found by test to be suitable as apaint remover.

EXAMPLE 5 Tetrahydronaphthalene 40.0 Benzol 15.0 Denatured ethyl alcohol10.0 Butylacetate 5.0 Methylene dichloride 20.0 Dodecylammoniumbentonite of Ex. 2 10.0

In preparing this compositiomthe same procedure as described for Example3 was followed,

with the exception that tetrahydronaphthalene and dodecylammoniumbentonite of Example 2 weremade into a slurry and the other ingredientsthen added. The resultant product was at least 8 carbonatoms.

an employed in the removal of an aged paint film. Further, the resultantproduct was successfully employed in the degreasing oi an internalcombustion engine which, in addition to the normal accumulation ofgrease from operatlon, had also been coated with grease to preventrusting during a prolonged period of storage.

' nxAMPLn e bentonites in paint, .varnish and lacquer removercompositions is by no means limited to the exampies above. In b, tbnltef 16 I acted lammo um en o Examp The any 25 above. This is an obviousadvantage in" that '1 and the dodecylammonium bentonite of Ex-i ample 2may be replaced. with other onium bentonites. As, for example,triph'enyllaurylphosphonium bentonite, triphenylcetylphosphoniumbentonite, 1 dimethyldilaurylammonlum bentonite; or onium bentonites ofthe closet arsonium,. 'stibonium, etc., without departing from the scopeof this invention. In order that the oniumbentonite compound produce thedesired bodying when added to solvents, it is felt that theonium'compound should contain at least one albl' group having a chainlength of obtained with onium bentonite compounds containing an alkylgroup having from 12 to 18- carbon atoms in the chain .inclusive.-'Laurylammonium bentonite, stearylammonium bentonite,dimethyldilaurylammonium' bentonite and triphenyllaurylphosphonium'bentonite are examples of onium bentonites with superior bodyingproperties in common organic solvents and may be substituted in Examples3, 4. and 6 with satisfactory results.

Among the solvents suitable are all solvents or combinations thereof.provided such solvents have the ability to dissolve or swell coatingfilms which one desires to remove.

Other solvents than those mentioned in the above examples maybe used.They may replace all or part of the solvents mentioned.Amongsuch-solvents are ketones, other than methylisobutyl-ketone,acetone, methyl-ethyl-ketone,

mesityl-oxide or diacetone alcohol. .The amount used in a removercomposition may be widely varied and if it is so desired, may form thesole liquid portion. Likewise other aromatic-.hydrocarbons may besubstituted for toluol: benzol, hi-flash naphtha, coal tar naphtha orhydrogenated solvents with aromatic contents ranging from 20-92 percentare suitable,

. alcohol portion can .be replaced with methyl,

18011 0971. 9 1 1 11. bu yl. 'amyl or octyl alcohol ,the ease orpreparation, whereby ammonium Maximum bodying' is in part or iuily oorcan also constitute the sole liquid portion. ther chlorides may be usedin. place of methylene dichloride; for example; vhutyl chloride,ethylene dichloride, carbon 5 tetrachloride, propylene dichloride or1,1,2-tri- J chlorethane maybe employed. 1

A remover made according to this invention was a found to adhere well tovertical surfaces. It remains as a covering of \ubstantially uniform.

w thickness over the entire surface on both the upper portion as well aslower portion. The active ingredientsof the composition areheld incontact with the coating for a time sufllcient to completely soften thecoating so that it may be is easily removed by scraping.

Furthermore, the residue, or non-volatile portion from ammoniumbentonite paint removers. is not objectionable in its etl'ect on theproperties of paints, .varnishes or lacquers applied 'over-- it. goPaints, varnishes or lacquers applied over the residue fromlcommon typepaint removers-dry slower, are soft and have poor adhesion to the base.There is little effect from the residue of the removers made from theexamples described scrupulously thorough cleaning' is not requiredquer'coats, and there isless danger of harmful eflects when thoroughcleaning is not possible. Another advantage .ot this invention lies inbentonites can be incorporated into the solvent blend by stirring byhand without the aid of ,machinery or other equipment. ,The system willgel within one hour to a gel-of desirable consistency. a .n

It will be readily understood that the above illustrative embodimentsare to be broadly interpreted and not to be taken as limiting the 40scope of the invention claimed.

The invention having thus been described, whatisclaime'dis:

l. A softener or remover for coatings; consist- I ing essentially of anorganic liquid of a generally coating penetrating and looseningcharacter,"

having colloidallydispersed therein in an amount sumcient tosubstantially increase the viscosity thereof, a cation-modified clay,originally exhibiting a, baseeexchange capacity of at least 25 and inwhich the inorganic cation has been exchanged foran onium baseoi a typecapable of and to an extent sufllcient to form with the clay anion anonium-clay, 2 grams of which oniumclay swelling to at least 16milliliters in nitrobenzene.

2. A softener or remover for coatings, con sisti'ng essentially ofanorganic liquid of a generally coating penetrating and looseningcharacter, having colloidally dispersed therein in an amount sufliciehtto substantially increase the viscosity thereof, a cation-modifiedbentonitic swelling clay, originally exhibiting a base-' exchangecapacity of at least and in which the inorganic cation has beenexchanged for an onium base of a type capable'ofand toan exingessentially of an organic liquid of a generally coating penetrating andloosening character, having colloidally dispersed therein in an amountsuflicient to substantially increase the viscosity thereof, acationmodiiled clay, originally exhibiting a base-exchange capacity ofat least 25 and in which the inorganic cation has been substantiallyreplaced by an onium ammonium ion which has at least carbon atoms in astraight aliphatic chain.

4. A softener or remover for coatings, consisting essentially of anorganic liquid of a generally coating penetrating and looseningcharacter, having colloidally dispersed therein in an amount sufiicientto substantially increase the viscosity thereof, a cation-modifiedmontrnorillonite and in which the inorganic cation has been replaced by50-300 ml. per 100 g. by an onium ammonium ion which has at least 10carbon atoms in a straight aliphatic chain.

5. In the art of making a softener or remover for coatings, comprisingtreating an organic liquid of a generally coating-penetrating andloosening character and in an amount sufiieient to substantiallyincrease the viscosity of the organic liquid, with a cation-modifiedclay, originally exhibiting a base-exchange capacity of at least 25 andin which the inorganic cation has been exchanged for an onium base of atype capable of and to an extent suflicient to form with the clay anionan onium-clay, 2 grams of which onium clay swelling to at least 16milliliters in nitrobenzene.

6. In the art of making a softener or remover for coatings, comprisingtreating an organic liquid of a generally coating-penetrating andloosening character with 5-15% of a cation modi tied clay, originallyexhibiting a base-exchange capacity of at least 25 and in which theinorganic cation has been exchanged for an onium base of a type capableof and to an extent suflicient to form with the clay anion anonium-clay,2 grams of which onium clay swellingto at least 16 milliliters innitrobenzene.

7. A softener or remover for coatings consisting essentially of anorganic liquid of a generally coating penetrating and looseningcharacter, having colloidally dispersed therein in an amount suflicientto substantially increase the viscosity thereof, a cation-modified clay,originally exhibiting a base-exchange capacity of at least 25 and inwhich the inorganic cation has been exchanged for an onium base with anorganic radical having a molecular area of at least 70 angstrom units,to an extent sufilcient to form with the clay anion an organophilicclay.

8. A softener or remover for coatings consisting essentially of anorganic liquid of a generally coating penetrating and looseningcharacter, having colloidally dispersed therein in an amount suiiicientto substantially increase the viscosity thereof, a cation-modified clay,originally exhibiting a base-exchange capacity of at least 25 and inwhich the inorganic cation has been exchanged for an ammonium base withan organic radical having a molecular area of at least angstrom units,to an extent suflicient to form with the clay anion an organophilicclay.

9. A softener or remover for coatings consisting essentially of anorganic liquid of a generally coating penetrating and looseningcharacter, having colloidally dispersed therein in an amount sufficientto substantially increase the viscosity thereof, an organophilicswelling onium ammonium bentonite having a hydrophobic radical with amolecular area of at least 70 square angstrom units.

10. A softener or remover for coatings consisting essentially of anorganic liquid of a generally coating penetrating and looseningcharacter, having colloidally dispersed therein in an amount suflicientto substantially increase the viscosity thereof, an organophilicoctadecyl ammonium bentonite.

11. A softener or remover for coatings consisting essentially of anorganic liquid of a generally coating penetrating and looseningcharacter, having colloidally dispersed therein in an amount suiiicientto substantially increase the viscosity thereof, an organophilic dodecylammonium bentonite.

EDWIN P. PETERSON. OSCAR P. MULLER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,033,856 Smith 7 Mar. 10, 19362,248,636 Marsden July 8, 1941 2,348,639 O'Brien May 9, 1944 2,388,082Roediger 1. Oct. 30, 1945 FOREIGN PATENTS Number Country Date 215,880Great Britain May 14, 1924 OTHER REFERENCES Hauser et al.: ColorReactions Between Clays and Amines, July 1940. Presented before theColloid Division, American Chemical Society, Cincinnati, Ohio, April 9,1940. Contribution from the Department of Chemical Engineering of the M.I. T., pages 1811-1814, vol. 62.

1. A SOFTENER OR REMOVER FOR COATINGS, CONSISTING ESSENTAILLY OF ANORGANIC LIQUID OF A GENERALLY COATING PENETRATING AND LOOSENINGCHARACTER, HAVING COLLOIDALLY DISPERSED THEREIN IN AN AMOUNT SUFFICIENTTO SUBSTANTIALLY INCREASE THE VISCOSITY THEREOF, A CATION-MODIFIED CLAY,ORIGINALLY EXHIBITING A BASE-EXCHANGE CAPACITY OF AT LEAST 25 AND INWHICH THE INORGANIC CATION HAS BEEN EXCHANGED FOR AN ONIUM BASE OF ATYPE CAPABLE OF AND TO AN EXTENT SUFFICIENT TO FORM WITH THE CLAY ANIONAN ONIUM-CLAY, 2 GRAMS OF WHICH ONIUM CLAY SWELLING TO AT LEAST 16MILLILITERS IN NITROBENZENE.